Quantum Chemical Calculations on Fentanyl Used as Potent Analgesic

Abstract

This current study dealt with the quantum chemical analysis on fentanyl compound, which is a potent synthetic analgesic. First of all, the geometry optimizations were carried out via Density Functional Theory (DFT) and Hartree-Fock (HF) methods in both the gas and the water phase. The B3LYP functional and the HF method were used with the 6-31G (d,p) and 6-31++G (d,p) basis sets. Computed structural parameters were compared with the data available in the literature and consistent results were obtained for all four different methodologies. Charge distributions of each atom of fentanyl were obtained by Mulliken and natural population analysis. Accompanied by calculated molecular descriptors, the results of frontier molecular orbital (FMO) analysis and natural bond orbital (NBO) analysis were reported. Finally, molecular electrostatic potential (MEP) analysis has been performed to estimate reactive sites for electrophilic and nucleophilic attack. Total density, ESP, MEP, and contour maps were visualized at B3LYP/6-31++G (d,p) level of theory.